Opcode/Instruction | Op/En | 64/32 bit Mode Support | CPUID Feature Flag | Description |
---|---|---|---|---|

66 0F 3A 44 /r ib PCLMULQDQ xmm1, xmm2/m128, imm8 |
RMI | V/V | PCLMULQDQ | Carry-less multiplication of one quadword of xmm1 by one quadword of xmm2/m128, stores the 128-bit result in xmm1. The immediate is used to determine which quadwords of xmm1 and xmm2/m128 should be used. |

VEX.128.66.0F3A.WIG 44 /r ib VPCLMULQDQ xmm1, xmm2, xmm3/m128, imm8 |
RVMI | V/V | Both PCLMULQDQ and AVX flags | Carry-less multiplication of one quadword of xmm2 by one quadword of xmm3/m128, stores the 128-bit result in xmm1. The immediate is used to determine which quadwords of xmm2 and xmm3/m128 should be used. |

Op/En | Operand 1 | Operand2 | Operand3 | Operand4 |

RMI | ModRM:reg (r, w) | ModRM:r/m (r) | imm8 | NA |

RVMI | ModRM:reg (w) | VEX.vvvv (r) | ModRM:r/m (r) | imm8 |

Performs a carry-less multiplication of two quadwords, selected from the first source and second source operand according to the value of the immediate byte. Bits 4 and 0 are used to select which 64-bit half of each operand to use according to Table 4-13, other bits of the immediate byte are ignored.

Imm[4] | Imm[0] | PCLMULQDQ Operation |
---|---|---|

0 | 0 | CL_MUL( SRC2^{1}[63:0], SRC1[63:0] ) |

0 | 1 | CL_MUL( SRC2[63:0], SRC1[127:64] ) |

1 | 0 | CL_MUL( SRC2[127:64], SRC1[63:0] ) |

1 | 1 | CL_MUL( SRC2[127:64], SRC1[127:64] ) |

1. SRC2 denotes the second source operand, which can be a register or memory; SRC1 denotes the first source and destination operand.

The first source operand and the destination operand are the same and must be an XMM register. The second source operand can be an XMM register or a 128-bit memory location. Bits (MAXVL-1:128) of the corresponding YMM destination register remain unchanged.

Compilers and assemblers may implement the following pseudo-op syntax to simply programming and emit the required encoding for Imm8.

Pseudo-Op | Imm8 Encoding |
---|---|

PCLMULLQLQDQ xmm1, xmm2 |
0000_0000B |

PCLMULHQLQDQ xmm1, xmm2 |
0000_0001B |

PCLMULLQHQDQ xmm1, xmm2 |
0001_0000B |

PCLMULHQHQDQ xmm1, xmm2 |
0001_0001B |

IF (Imm8[0] = 0 ) THEN TEMP1←SRC1 [63:0]; ELSE TEMP1←SRC1 [127:64]; FI IF (Imm8[4] = 0 ) THEN TEMP2←SRC2 [63:0]; ELSE TEMP2←SRC2 [127:64]; FI For i = 0 to 63 { TmpB [ i ]←(TEMP1[ 0 ] and TEMP2[ i ]); For j = 1 to i { TmpB [ i ]←TmpB [ i ] xor (TEMP1[ j ] and TEMP2[ i - j ]) } DEST[ i ]←TmpB[ i ]; } For i = 64 to 126 { TmpB [ i ]←0; For j = i - 63 to 63 { TmpB [ i ]←TmpB [ i ] xor (TEMP1[ j ] and TEMP2[ i - j ]) } DEST[ i ]←TmpB[ i ]; } DEST[127] ← 0; DEST[MAXVL-1:128] (Unmodified)

IF (Imm8[0] = 0 ) THEN TEMP1←SRC1 [63:0]; ELSE TEMP1←SRC1 [127:64]; FI IF (Imm8[4] = 0 ) THEN TEMP2←SRC2 [63:0]; ELSE TEMP2←SRC2 [127:64]; FI For i = 0 to 63 { TmpB [ i ]←(TEMP1[ 0 ] and TEMP2[ i ]); For j = 1 to i { TmpB [i]←TmpB [i] xor (TEMP1[ j ] and TEMP2[ i - j ]) } DEST[i] ← TmpB[i]; } For i = 64 to 126 { TmpB [ i ]←0; For j = i - 63 to 63 { TmpB [i]←TmpB [i] xor (TEMP1[ j ] and TEMP2[ i - j ]) } DEST[i] ← TmpB[i]; } DEST[MAXVL-1:127] ← 0;

(V)PCLMULQDQ: __m128i _mm_clmulepi64_si128 (__m128i, __m128i, const int)

None.

See Exceptions Type 4, additionally

#UD | If VEX.L = 1. |